Index help

[Peter1973]

I am using the following :
=INDEX('Rota April to July'!$A$7:$A$1000,MATCH($B5,'Rota April to July'!$C$7:$C$1000,0))

I would like to if the cell in $C$7:$C$1000 is blank use $D$7:$D$1000 instead.

Any help appreciated

 

[Dryver14]

=if(INDEX('Rota April to July'!$A$7:$A$1000,MATCH($B5,'Rota April to July'!$C$7:$C$1000,0))="",
INDEX('Rota April to July'!$A$7:$A$1000,MATCH($B5,'Rota April to July'!$D$7:$D$1000,0)),
INDEX('Rota April to July'!$A$7:$A$1000,MATCH($B5,'Rota April to July'!$C$7:$C$1000,0))

seems long i know, there may be a better way